1. Field of the Invention
See-thru or one-way films have become well known and are used for various purposes, mainly advertising displays. Most see-thru films are fabricated having a substrate which is perforated and which is coated on one side with a black pigment. The opposite side is white opaque and printed with an image and conventional practice is to print the image by use of silkscreening or lithography. The perforations permit viewing in one direction which is substantially unobstructed. The white opaque surface receives the image which is viewable from the opposite side. For example, see Pat. Nos. 4,883,556 and 4,940,622 to Leavitt which teach silkscreening a perforated substrate. Similarly, U.S. Pat. No. 5,525,177 teaches a printing or image transfer method using an electrostatic process in which a reverse image is transferred to a surface of a perforated membrane.
2. Background of the Invention
The problem with using conventional printing methods such as screen printing is that screen printing is not cost effective for short runs, is time consuming and the resulting product while acceptable, does not have a high quality of resolution. Also, screen printing images cannot be tiled for unique one-of-a-kind graphics. Similarly, deficiencies exist with electrostatic processes.
Electrostatic printing is applicable to short-run graphics. However, the equipment necessary for electrostatic printing is much more expensive than silkscreening, thermal or piezo ink jet printing and is more complicated involving the use of a laminator to transfer the printed image to an electrostatically charged substrate.
The present invention relates to an improved method for producing or imaging see-thru panels or films with ink jet technology. See-thru films have the advantage that an image may be applied and viewed from one side and, because of the perforations, substantial light passes through the film allowing the viewer relatively unobstructed vision from the opposite side. Thus, see-thru films are widely used on such advertising applications as the signage applied to the sides of vehicles such as buses, allowing the passengers a relatively unobstructed view. See-thru films are also used where visibility for security purposes is important. Glass panels such as windows and cooler cases are other typical applications for these types of film.